we have an immersion heater which is hooked up with 2 switches because of economy 7 electricity. Recently we have not been getting hot water from about 3pm (the switch for the top up element is on with a red light). we called in a plumber who took a look at it and tried to blame it on the economy 7 side of things and that he could not do anything because he was not an electrician, he did not seem to really check out the heater much.

Does this sound like a plumbing issue or an electric one? I dont want to waste a call out charge for an electrician if its something he can't fix!

Heating Engineers as they call them selves will normally do both. One does have to be careful when two ways of heating water are used. For safety the thermostats normally have a non resettable over temp switch so if they go wrong it will fail safe. However when two forms of heating are used then the over temp switch can be tripped with the other form of heating so it normally has a re-settable button on it. It does not really matter if two electric or electric and solid fuel once two are used then re-settable thermostats should be used.

However that is in ideal world and to get the thermostat with reset button is not so easy. If the thermostat is the problem the electrician will often change them both to be on safe side.

However if the problem is element then it is very easy to rip the tank removing old unit and of course it will need draining. Many electricians will not try to remove the element and will just disconnect ready for plumber to remove.

The heating and ventilating guys will normally do both.

Of course you can always ask on the phone to see if they will do both.

Unfortunately you have a catch 22 situation. I would think its 85% electrical, but many electricians wont change the immersion without a plumber because some plumbing systems are a lot more complicated than others & need to be drained off in a certain way.
I would personal call a registered plumber & ask before they come if they will deal with the electrical testing & connections if needed. Most corgy (Or the new version) fitters should be able to do this.

Sounds electrical - the lower immersion heats the whole tank overnight, the upper immersion is to top you up during the day. If you've used all the overnigth heat by 3pm you need to run the upper immersion to top up - it only heats the water in the upper third of the tank. As it isn't heating, the most likely culprit is the thermostat, which fits down the middle of the immersion heater element and switches the electricity on and off depending on the temperature of the water. Depending how handy you are with electrics, try a new thermostat - or get in an electrician to fit one for you.

[quote="pjcomp"]Sounds electrical - the lower immersion heats the whole tank overnight, the upper immersion is to top you up during the day. If you've used all the overnigth heat by 3pm you need to run the upper immersion to top up - it only heats the water in the upper third of the tank. As it isn't heating, the most likely culprit is the thermostat, which fits down the middle of the immersion heater element and switches the electricity on and off depending on the temperature of the water. Depending how handy you are with electrics, try a new thermostat - or get in an electrician to fit one for you.[/quote]

Unless tested then you need to change both thermostats as lower one if faulty can cause upper one to fail. However I feel trial and error maintenance can work out costly and I would think better to have it all tested.

The Insulation tester is not cheap and although Electricians with have one and Heating engineers may have one it is unlikely that a Plumber will have one. They are often called "Mega's" and they cost around £200 and without one the element can't be tested.

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